Testing TRIM

A firmware update gives you TRIM support, but we should probably test to make sure it's actually working.

First up, the Intel X25-M G2 with the TRIM firmware. I ran a 4KB random write test across the entire 80GB LBA space for five minutes. I ran the test again afterwards and recorded the average transfer rate for each run:

4KB Random Write, IOQ=16 Run 1 Run 2
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 13.8 MB/s

 

As expected, performance goes down as the drive fills up. The second run is much slower than the first.

Now look at the two runs if we format the drive in between. The format under Windows 7 triggers a TRIM of all invalid data, meaning all the jibberish we generated in the first run is gone and the second run now runs at full speed:

4KB Random Write, IOQ=16 Run 1 Run 2 after Format
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 38.0 MB/s

 

Obviously you don’t usually write a bunch of garbage to your drive then format and repeat, but we’re trying to confirm that TRIM works here; it does. Windows 7 will actually take noticeably longer to format a drive that supports TRIM and has data on it. It still completes in less than 30 seconds on these SSDs, but it's a lot longer than the few seconds it used to take before TRIM.

This confirms that TRIM works on a format, but what about if you delete a partition? To find out I created a partition on my X25-M G2, filled it with data, deleted the partition and ran my 4KB random write test across all LBAs. If deleting a partition forces TRIM I should see new-performance out of the G2:

4KB Random Write, IOQ=16 Run 1 Run 2 after Deleting Partition
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 17.9 MB/s

 

Performance drop. Formatting a partition causes the contents to be TRIMed, but just deleting a partition doesn’t. This means if you accidentally delete a partition you can still retrieve your data, however there’s no way to go back from a format.

What about file deletion? I performed the same test. Created a partition, filled it with garbage but then deleted the garbage before deleting the partition and running my 4KB random write test. Deleting data should force a TRIM:

4KB Random Write, IOQ=16 Run 1 Run 2 after Deleting All Files
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 40.4 MB/s

 

Indeed it does. You no longer have to worry about performance dropping over time. When you delete a file it’ll eventually be nixed on the SSD as well. Below we have the actions that will force a TRIM of data under Windows 7:

Windows 7 File Delete Partition Format Partition Delete
TRIM? Yes Yes No

 

Formatting your drive now actually does something. You no longer have to boot to DOS and secure erase your SSD before installing Windows, just quick format the partition before installing Windows 7.

I performed the same tests on an Indilinx MLC based SSD, this time a SuperTalent UltraDrive GX with the 1819 TRIM-enabled firmware. The results were identical:

4KB Random Write, IOQ=16 Run 1 Run 2 After Format After File Delete
SuperTalent (Indilinx) UltraDrive GX TRIM Firmware v1819 17.8 MB/s 14.1 MB/s 17.8 MB/s 17.8 MB/s

 

We have TRIM working on both Indilinx (from SuperTalent/OCZ) and Intel drives. Sweet.

Index Wipe When You Can’t TRIM
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  • Pandamonium - Monday, October 26, 2009 - link

    The 2nd gen X18-M isn't available as far as I can tell. It kind of shafts us tablet and ultraportable users out of the SSD market for another round =/
  • Cavicchi - Monday, October 26, 2009 - link

    "You no longer have to boot to DOS and secure erase your SSD before installing Windows, just quick format the partition before installing Windows 7."

    I always thought the "quick format" doesn't wipe the entire drive as clean as a full/long format. Does the above mean we only need to do a quick format to wipe a drive clean to install Windows 7?

    Also, I noticed Superfetch, Prefetch, and Ready Boost are enabled in Windows 7 x64 with my X25-M G2 160GB drive installed.
  • Voo - Monday, October 26, 2009 - link

    Logically when a TRIM command is sent to the drive you lose all the data that was saved there.

    So, there's no difference between full/quick format or anything else as long as it triggers the TRIM command..
  • Beno - Monday, October 26, 2009 - link

    "SSDs are made up of millions of NAND flash cells. They can be written to in groups called pages (generally 4KB in size) but can only be erased in larger groups called blocks (generally 128 pages or 512KB). These stipulations are partially the source of many SSD performance issues."
    but isnt it possible to erase data in 4KB, the same way they are written?
  • krumme - Monday, October 26, 2009 - link

    Where does speed matter most?
    Getting some sense into the g2 hype
    Now you can have a job with a Dell and a hd with samsung controller without quitting the job

    Thanx Anand for always improving your site and letting us learn
    Thats whats move this boys-toy business forward


  • flynace - Monday, October 26, 2009 - link

    If you set up a software RAID-0 array within Windows 7 will it support TRIM?
    Or is TRIM not possible on any form of RAID (OS, BIOS, HW, etc.)?

    And does aliging the partitions make any difference on these drives?
  • Voo - Monday, October 26, 2009 - link

    Iirc Anand stated in some of his articles that there's no TRIM support for raid, because the controller had to forward the commands.

    But imho it sounds not like a unconquerable problem, so it's probably only a question of time.
  • flynace - Tuesday, October 27, 2009 - link

    Thanks. I assume Intel will update their drivers to support RAID TRIM eventually, but if you don't have an 'R' tybe Intel ICH, does Win7 support TRIM if you set up a software RAID array in the OS still using the MS AHCI drivers?
  • Willardjuice - Monday, October 26, 2009 - link

    Did Intel update their Windows 7 sata/raid drivers to also include TRIM support? Or do we have to use the drivers provided by Microsoft?
  • DoveOfTheSouth - Monday, October 26, 2009 - link

    Another great SSD article from Anand (thank you so much)!

    But I'm really disappointed that you have to use the Microsoft Win 7 disk driver to get TRIM. It has a huge problem.

    Based on my experience, I would normally strongly recommend that the first thing you do when installing Win 7 is replace the Microsoft driver with the latest Intel Matrix Storage Manager.

    The following link describes the problem (long periods of system non-responsiveness) you can get with the Microsoft driver and at least some PCs, and how to fix it:
    http://blogs.zdnet.com/Bott/?p=1431&page=3&...">http://blogs.zdnet.com/Bott/?p=1431&page=3&...

    I had exactly the same crippling problem on a Dell Dimension 9100 which baffled me until I replaced the Microsoft driver with IMSM - problem disappeared instantly.

    Okay it was bit of an old PC but of the 3 I have been testing with Win 7 for the last couple of months, it was the only one that used the Microsoft driver instead of IMSM (it was an XP upgrade ie OS reinstall, the others upgrades from Vista). So I don't know how widespread the problem with the Microsoft driver is, it hit my only PC that was a candidate, but I'd be pretty wary.
    Otherwise Win 7 has been great.

    So it looks like you have a choice: IMSM with no TRIM or a buggy Microsoft driver with TRIM.

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